Rotary kiln



May 23, 1933.

A. B. ZAHN ROTARY K ILN Filed April 19, 1952 2 Sheets-Sheet l W mf 2i 'May 23, 1933'. a ZAHN 1,910,873

' ROTARY KILN Filed April 19, 1952 2 Sheets-Sheet, 2

INVENTOR KMIMI Patented May 23, 1933 i STATES PATENT OFFICE R'OHIE Bg ZAHN, or BROOKLYN, NEW YORK, Assxenorc TO r: L; smn'rn 8500., on NEW c i g YORK, min, AconronA'rIoNor mzwmnsny 30mm? KILN Q ,Application filed a rnis, 1932.1 seminb. 606,130:

.Thiseinventi'on relates to the burning of slurry, in rotary, kilns and more particular: ly-to use in SU Ch klllLS OfTCTOSS chains by i which the transmission of heat from the hot products of: combustion tothe slurry is pro meted, The,m arrangement of such cross chains in :rotary kilnsw and the manner in,

wl lddh f tll ey, function. are fully described in Letters Patent of jthe United States No. :;1,3;13,281adatedfAugust 19,1919 and "granted toFQIf. Smidtha -rgzflo, the assignee in the presentucase,,upontthe application of J. S. Fastingq The-installation. of such chains in rotary-kilns employed in the wet process of i macementmanufaeture hasbeen of great value to; the cement-industry vof the United States,

the annualfsavingrin fuel cost to the cement manufacturers, effected thereby, being estimated conservatively at one and one-half mu lionl dollars. In the long. continued and widespread use of such cross chains under the ob servation of the engineers of the assignee hereineffortsihave been made to increase the efficiency; of fsuch heat; transmission devices.

2513 It ihasfbeen realized, of course, that the transmission-of heat ght be increased by anine crease in ithe number of; chains installed in a kilng orby increasingthelength of the chainsiemployed," but it has been realized 3M3 also that thereby the dead load carriedby the ki-lnrin its. {rotation would. be increased also and that, particularly ifit should be sought to increasel the length of the chains usedsthewearlon the kiln lining and on the: Bflfichains .themselveswould be increased. In.

the continued study of the problem presentedlit'hlas been-found, in the development of, the; present invention, that the increase of efficiency-in thetransmission of heat, withmslout increase ofnvearof the chains and of the kiln lining, can be secured by such deformation of the chains as will increase the heat absorbingusnrface ofthe chains: without i11- CEEZLSlIlgthBH length. In accordance with ithe invention, therefore, thechains employed for the purpose rotary kilns are deformed,

shorter than: those commonly employed,

whereby wear of the chains and liningiof the kiln considerably;diminished;

The invention :will be more fully explained hereinafter with reference to theaccompany:

ingdrawings in which it is illustrated, and in which:

Figure 1 is aview in elevation of arotary kilnflto which th'epresent improvements may be applied. i i

Figure 2 is a view in elevation, on a somewhat larger scale, of the feeding end of i the Figurc-3 is a cross-sectional perspective view, partly diagrammatic, showing one chainiin the position which it occupies-ati one point in therotationofthekiln, the pos itions of the other chains of the same series being indicatedby broken lines. t

Figure 4 is a diagrammaticview of a development of the inner wall of thekiln indicatingthe disposition of the crosschains.

Figure 5 is a detail view showingoneaof the improved links as having its sides bent inward toward the longitudinal axis, the ad.

jacent linkbeing shown in section.

Figure 6 is a detail view showing, two interconnected links withtheir sideswbent in toward the longitudinal axis and pressed or stamped to form flattened projections;

Figure 7 is a detail view in section onthe plane indicated by the broken line,77-of Figured T kiln.

Figure 8 is a conventional view illustrating the advantage gained by the invention.

As represented in Fig. 1, the kiln a may be of ordinary construction, being provided at its feeding end with a suitable supply chute Z) through which the slurry is fed to the kiln and at its other end with a suitable combustion chamber. As is well understood more or less of the slurry, in the rotation of such a kiln, adheres to the inner wall of the kiln, is carried upward with the wall of the kiln, in the direction of rotation, and is continuously falling or slipping back toward the lowest part of the kiln. The chains 0, which are secured at their ends to the inner wall of the kiln by suitable bolts, as indicated at d, and are preferably arranged helically in the kiln, as indicated particularly in Fig. 4, dip into the wet slurry in the rotation of the kiln and carry the adhering slurry upward and across the flowing stream of the hot products of combustion. Preferably the chains are somewhat slack, so that the bight of each chain shall lie in the slurry in the lower part ofthe The chains themselves, as they pass through the hot products of combustion in the kiln, absorb heat from such products of combustion and give up the heat to the slurry with which they are coated, the slurry which passes through the current of hot gases itself absorbing heat from the hot gases. As indicated in the drawings many chains are provided and they are preferably arranged helically, that is, with the leading end of each chain out of the plane of the following end so that the movement of the slurry through the kiln is promoted. As will be understood the slurry which dries on the chains is broken away from the chains by the flexing of the slack chains and falls into the slurry below and further when the chains are sufficiently slack to rest upon the inner wall of the kiln, as indicated in the drawings, the incrustation of'slurry on the wall of the kiln will be prevented there,- by. Preferably the two ends of each chain are connected to the wall of the kiln about 120 apart, but it will be understood that the specific arrangement of the chains, both as regards their connection to the Wall of the kiln and as regards the degree of slackness and the degree of obliquity of the chains will be determined by the conditions of operation.

As thus far described the arrangement and operation of the chains are substantially the same as described in said Patent No. 1,313,281.

For the purpose of increasing the heat absorbing and heat transmitting surface of the.

chains without increasing their length or number, each link 0 of each chain is deformed 3 as by having its sides pressed in, as indicated at 0 toward its longitudinal axis whereby the total length of the chain is materially decreased, but without impairing the flexibility I of the chain or increasing its weight. For

= the purpose of further increasing the area of the absorption surface each link is further deformed, as by stamping or pressing, to form projecting portions 0 with flat surfaces, as at 0 the increase of surface area of each link being thereby increased without affecting the flexibility of the chain or increasing its weight.

The chains ordinarily used for the purpose. described are formed in electric welding machines from rods diameter. ard chain, such as has been used hertofore, made without deformation of the links, has a total surface area of 93 square inches for each foot in length of the chain, with a wei ht of 4.1 pounds per foot. A chain formed 1n the same manner and of rods of the same diameter, but deformed as described, has a surface area of 109.5 square inches for each foot in length of the chain with a weight of 1.796

pounds for each foot in length. The, improved chain has therefore a surface area approximately 17% greater than a chain of the same length without deformation of the links and a weight about 17 greater.

For purposes of comparlson 1t may be pointed out that a standard chain made of' 2;" rod has a surface area of 110 square inches per foot and a weight of 5.8 pounds per foot, that is to say, for approximately the same surface area such a standard chain has a weight about 12% greater than a special chain of the same length. The relative lengths of a special chain having links deformed in accordance with the invention, and of a standard chain of the same length before deformation, are indicated, with but slight exaggeration, in Fig. 8 of the drawings.

I claim as my invention:

1. The combination with a rotary kiln for burning slurry of cross chains secured to the interior of the kiln near the feeding end of the kiln and adapted, in the rotation of the kiln, to be dipped into the wet slurry, to become coated thereby, and to lift the slurry into the path of the hot products of combustion, each link of each chain being deformed to shorten its length for the purpose of giving a greater surface area in proportion to its length. i

2. The combination with a rotary kiln for burning slurry of cross chains secured to the interior of the kiln near the feeding end of the kiln and adapted, in the rotation of the kiln, to be dipped into the wet slurry, to become coated thereby, and to lift the slurry into the path of the hot products of combustion, each link of each chain being deformed to shorten its length and having projections with flattened sides all for the purpose of giving a greater surface area in proportion to its length.

8. The combination with a rotary kiln for burning slurry of cross chains secured to the interior of the kiln near the feeding end of The standthe kiln and adapted in the rotation of the kiln, tobe dipped into the Wet slurry, to become coated thereby, and to lift the slurry into the path of the hot products of combustion, each link of each chain having itsfsides bent inward toward its longitudinal axis to shorten its length for the purpose of giving a greater surface area in proportion to its length.

This specification signed this 5th day of April A. D. 1932.

ARCHIE B. ZAHN. 

